January 2020
Intermediate to advanced
356 pages
6h 4m
Chinese
Content preview from Swift游戏开发经典实例
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章
MPMusicPlaybackState.playing
当前正在播放。
MPMusicPlaybackState.paused
当前正在播放，但处于暂停中。
MPMusicPlaybackState.interrupted
当前正在播放，但被临时中断（如有电话呼入）。
MPMusicPlaybackState.seekingForward
当前正在快进。
MPMusicPlaybackState.seekingBackward
当前正在快速倒放。
通过注册
MPMusicPlayerControllerPlaybackStateDidChange
通知，我们可以获得
回放状态的改变。同样，通过注册
MPMusicPlayerControllerNowPlayingItemDidCh
ange
通
知，我们也可以获得播放内容改变通知。
4.9
让用户选择音乐
问题
有时候，我们想让用户选择要播放的音乐。
解决方案
我们可以显示一个
MPMediaPickerController
，让用户选择要播放的音乐。首先，
让视图控制器实现
MPMediaPickerControllerDelegate
协议：
class ViewController: UIViewController, MPMediaPickerControllerDelegate {
接着，在需要显示
MPMediaPickerController
的地方，使用如下代码：
let picker = MPMediaPickerController(mediaTypes:MPMediaType.anyAudio) ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.